Effects of supraphysiologic glucose and palmitate on the content of intracellular triglyceride and expression of FAT/CD36 in β-cells

Objective To observe the effects of supraphysiologic levels of glucose and palmitate on the intracellular triglyceride(TG)content and FAT/CD36(FAT:fatty acid translocase)expression in β-cells.Methods NIT-1 cells were exposed to 25 mmol/L glucose(HG group)and 0.25 mmol/L palmitate with either 5 mmol/L(HP group)or 25 mmol/L glucose(GP group)for 24 h.Control group was provided by cells cultured at 5 mmol/l glucose.TG content,insulin level and expressions of FAT/CD36 mRNA and protein were detected respectively.Results ①Cells cultured in elevated glucose and/or palmitate showed an increased TG content and a decreased glucose-stimulated insulin secretion(GSIS)vs.NC group.The most significant changes of TG and GSIS were observed in GP group.②FAT/CD36 expression was significantly enhanced in both HG and GP groups vs.NC group(P0.01),but palmitate had no effect on the FAT/CD36 expression at either 5 mmol/L or 25 mmol/L glucose.Conclusions In the presence of elevated palmitate levels,the prolonged exposure of β-cells to supraphysiologic concentrations of glucose could further increase TG content and inhibit GSIS,for which the high expression of FAT/CD36 induced by enhanced glucose concentrations may be one of important mechanisms.